A power supply control method and system for a secondary distribution power supply panel

Abstract

The application relates to the technical field of power supply automatic switching of power supply panels, in particular to a power supply control method and system for secondary power distribution of power supply panels, which comprises the following steps: collecting voltage data of each phase in the running process of a power supply panel within a preset time period; comparing the effective values of the voltage data of each phase within the preset time period with a preset threshold value to extract a fault phase and a phase to be analyzed; if there is at least one fault phase, switching the power supply of the power supply panel; if there is only the phase to be analyzed, obtaining a cycle zero point sequence of each phase by analyzing zero sequence faults of the power supply of the power supply panel; calculating the difference of the same position elements between the cycle zero point sequences of any two phases, obtaining the phase deviation between the any two phases by combining the deviation between the difference and a preset standard difference, and controlling the switching of the power supply of the power supply panel. The application aims to improve the sensitivity of fault detection of the power supply of the power supply panel and guarantee the stable operation of the power supply panel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automatic switching of power supply screen power supply, and particularly relates to a power supply control method and system for secondary power distribution of power supply screen. BACKGROUND

[0002] Secondary power distribution is a process in which high-voltage power is converted into low-voltage power and distributed to end users in a power system. During the operation of the power supply screen in secondary power distribution, the power supply screen generally uses dual power supply, including a main power supply and a backup power supply. In normal circumstances, the main power supply is used for power supply. When the main power supply fails, the backup power supply is automatically switched to for power supply. Before automatically switching the power supply of the power supply screen, the running state of the main power supply usually needs to be monitored.

[0003] The traditional power supply running state monitoring method mainly monitors the power supply voltage by presetting a voltage threshold. However, in a multi-phase power supply, when a zero sequence fault occurs, that is, the phasor sum of the three voltage phases is not zero due to three-phase voltage imbalance, if the three-phase voltage imbalance is slight, the voltage of each phase may still be within the normal threshold range, but at this time, the multi-phase power supply has a zero sequence fault, making it difficult to accurately detect the fault in time through voltage threshold monitoring, resulting in an insensitive fault detection result. SUMMARY

[0004] In view of the above, it is necessary to provide a power supply control method and system for secondary power distribution of power supply screen, which, compared with the traditional power supply control method of power supply screen, improves the sensitivity of fault detection of the power supply of the power supply screen, and ensures stable operation of the power supply screen:

[0005] In a first aspect, the embodiments of the present application provide a power supply control method for secondary power distribution of power supply screen, which comprises the following steps:

[0006] Collecting voltage data of each phase in the running process of the power supply screen within a preset time period;

[0007] By comparing the effective values of the voltage data of each phase within the preset time period with a preset threshold, extracting a fault phase and a to-be-analyzed phase, and if there is at least one fault phase, switching the power supply of the power supply screen;

[0008] If there is only a to-be-analyzed phase, by analyzing the zero sequence fault of the power supply of the power supply screen, obtaining a cycle zero point sequence of each phase;

[0009] Calculating the difference between the same position elements of the cycle zero point sequences of any two phases, and combining the deviation between the difference and a preset standard difference to obtain a phase deviation between the any two phases;

[0010] Based on the phase deviation, the power supply switching of the power supply screen is controlled.

[0011] In one embodiment, the method for extracting the fault phase and the phase to be analyzed is as follows:

[0012] The effective value is the root mean square value of all voltage data of each phase in the preset time period;

[0013] When the effective value of any phase is less than a preset first threshold value, the any phase is determined as a fault phase;

[0014] When the effective value of the any phase is greater than or equal to the preset first threshold value and less than or equal to a preset second threshold value, the any phase is determined as a phase to be analyzed.

[0015] In one embodiment, the process for obtaining the cycle zero point sequence is as follows:

[0016] The time point at which the voltage data is 0 is recorded as a 0 value time point, for the any phase, the order of all the 0 value time points in the preset adjacent time domain of each 0 value time point in all collection time points is arranged from small to large to form a time sequence of each 0 value time point, and the mean value of all elements in each time sequence is calculated;

[0017] For any time sequence and its adjacent previous time sequence, the difference between each element in the any time sequence and the mean value of the previous time sequence is calculated;

[0018] The cycle zero point difference degree of each element in the any time sequence is obtained by comparing a first preset value with the difference corresponding to each element in the any time sequence, and the element serving as a cycle zero point is extracted from the any time sequence through the cycle zero point difference degree;

[0019] All cycle zero points of the any phase are arranged in time sequence to form a cycle zero point sequence of the any phase.

[0020] In one embodiment, the cycle zero point difference degree is a difference value between the first preset value and the difference corresponding to each element in the any time sequence.

[0021] In one embodiment, the cycle zero point is the element with the smallest cycle zero point difference degree in the any time sequence.

[0022] In one embodiment, the calculation relationship of the phase deviation is as follows:

[0023] In the formula, Pl A,B represents the phase deviation between phase A and phase B; M A,B represents the minimum value of the number of elements in the cycle zero point sequence of phase A and phase B; Z A,x , Z B,xrepresents the xth element in the periodic zero point sequence of phase A and phase B respectively; P represents the number of voltage data collected within a preset time length; n represents the number of AC cycles within the preset time length;

[0024] According to the calculation method of the phase deviation between phase A and phase B, the phase deviation between phase A and phase C and the phase deviation between phase B and phase C are calculated respectively.

[0025] In one embodiment, when the phase deviations between any two phases are less than a second preset value, the power supply of the power panel is not switched; otherwise, the power supply of the power panel is switched.

[0026] In one embodiment, before switching the power supply of the power panel, it is necessary to detect the startup status of the backup power supply and the distribution of the output voltage and frequency.

[0027] In one embodiment, after the power supply of the power supply panel is switched from the main power supply to the backup power supply, feedback control technology is used to correct the phase corresponding to the phase deviation greater than the second preset value based on the phase deviation greater than the second preset value. After the correction is completed, the power supply of the power supply panel is switched from the backup power supply to the main power supply.

[0028] In the second aspect, an embodiment of the present application also provides a power supply control system for a power supply panel of secondary power distribution, comprising a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-mentioned power supply control methods for a power supply panel of secondary power distribution.

[0029] This application has at least the following beneficial effects:

[0030] The application can determine whether the power supply screen power supply has a ground fault by comparing the effective value of the voltage data of each phase within a preset time length with a preset threshold value according to the change characteristics of the voltage data of the fault phase and the normal phase when the power supply screen power supply has a ground fault, and if a ground fault occurs, the power supply screen power supply is switched from the main power supply to the standby power supply, which can ensure stable operation of the power supply screen. Further, by analyzing the time distribution of the voltage data being 0 and calculating the cycle zero point of each phase, the cycle zero point generated due to voltage instability and environmental noise can be avoided, thereby improving the accuracy of calculating the phase deviation between adjacent phases according to the cycle zero point, determining whether the phase deviation between adjacent phases exceeds the normal range, and if it does, switching the power supply screen power supply from the main power supply to the standby power supply to avoid still using the main power supply for power supply when the phase deviation of the main power supply is abnormal, which can affect the stability of the output power. By analyzing the voltage data during the operation of the power supply screen, various faults of the power supply screen power supply can be found in time, the sensitivity of fault detection of the power supply screen power supply is improved, accurate basis is provided for switching control of the power supply screen power supply, and stable operation of the power supply screen power supply is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art and the advantages thereof, a brief introduction will be given to the drawings needed in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative effort.

[0032] Figure 1 A step flow chart of a secondary distribution power supply screen power supply control method provided by an embodiment of the present application is shown in the figure.

[0033] Figure 2 A schematic diagram of star connection mode is shown in the figure.

[0034] Figure 3 A switching control flow chart of the power supply screen power supply is shown in the figure. DETAILED DESCRIPTION

[0035] In the description of the embodiments of the present application, the words "exemplary", "or", "for example" are used to mean example, illustration or description. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the words "exemplary", "or", "for example" are intended to present the relevant concept in a specific manner.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. It will be understood that unless otherwise specified, "or" as used herein is inclusive or meant to be the same as "and / or." Unless otherwise specified, "a" includes "one or more" in the present application.

[0037] It should also be noted that the terms "first", "second" and "third" are used herein to distinguish similar objects, and are not intended to describe a specific order or sequence.

[0038] The specific scheme of the power supply control method and system of the power supply panel of the secondary power distribution provided by the present application will be described in detail below in combination with the drawings.

[0039] Please refer to Figure 1 , which shows the step flowchart of the power supply control method of the power supply panel of the secondary power distribution provided by an embodiment of the present application, which comprises the following steps:

[0040] Step S101, collecting the voltage data of each phase in the running process of the power supply panel within a preset time period.

[0041] In the power supply of the power supply panel, three phase lines are used, each phase line has a phase voltage of 220V, and the three phase lines are combined to form a bus voltage of 380V through a star connection mode. The schematic diagram of the star connection mode is shown in Figure 2 In three-phase alternating current, the phase difference between adjacent phases is The phase difference makes the three-phase alternating current can provide stable power output, suitable for various industrial and commercial electrical equipment. The relationship between single-phase voltage and bus voltage is:

[0042] In the formula, V line represents the bus voltage; V phase represents the single-phase voltage.

[0043] The power supply of the power supply panel has three phases, and an intelligent electric meter is installed on each phase line to collect the voltage data of each phase of the power supply panel.

[0044] In the present embodiment, the voltage data is collected within a preset time period, the length of the preset time period is 0.1s, and the collection frequency of the voltage data is 10kHz. The length of the preset time period and the value of the collection frequency are preset by human, and the implementer can set them by himself, which is not specially limited in the present application.

[0045] For each phase line of the power supply screen power supply, the signal form of the voltage of the phase line in the time domain is a sine signal. Therefore, in order to avoid the influence of environmental noise in the collected data, in the present application, a moving average filtering algorithm is used to filter the voltage data of each phase collected. The moving average filtering algorithm is a known technology, and will not be described herein. The implementer can select other feasible filtering methods.

[0046] In step S102, the faulty phase and the phase to be analyzed are extracted by comparing the effective values of the voltage data of each phase within the preset time period with the preset threshold value. If there is at least one faulty phase, the power supply of the power supply screen is switched.

[0047] The voltage phase with a ground fault is referred to as a faulty phase, and the voltage phase without a ground fault is referred to as a normal phase. When the power supply screen power supply has a faulty phase, the voltage of the faulty phase will drop to 0 or close to 0, and the voltage of the normal phase will rise to the bus voltage. For a normally operating power supply, a voltage error of ±20V is usually allowed in the phase line, i.e., the range of the normal single-phase voltage is between 200V and 240V. Since the voltage of the normal phase is close to the bus voltage and the voltage of the faulty phase is close to 0 when a phase ground fault occurs, in order to identify the fault of the power supply screen power supply, a first threshold value and a second threshold value are respectively preset. In order to ensure the accuracy of detection, the value range of the first threshold value is [20, 180], and the value range of the second threshold value is [260, 360], because a 20V error is left for the voltage.

[0048] In the present embodiment, the values of the first threshold value and the second threshold value are 90 and 310 respectively. On the basis of ensuring that the values of the first threshold value and the second threshold value can identify the faulty phase and the normal phase, the implementer can set the values of the first threshold value and the second threshold value.

[0049] Based on the above analysis, by comparing the effective values of the voltage data of each phase within the preset time period with the first threshold value and the second threshold value, the ground fault identification value of each phase is obtained, and the expression is:

[0050] In the formula, Flag A represents the ground fault identification value of the A phase of the power supply screen power supply; F A represents the effective value of the A phase of the power supply screen power supply; T d represents the first threshold value; T grepresents the preset second threshold value; N1, N2 and N3 represent a first preset constant, a second preset constant and a third preset constant respectively, and represent a fault phase, a phase to be analyzed and a normal phase respectively. The effective value of the A phase is the root mean square value of all voltage data of the A phase in the preset time period, and the calculation of the root mean square value is a known technology, which will not be described herein.

[0051] In this embodiment, the values of N1, N2 and N3 are -1, 0 and 1 respectively, and the values of N1, N2 and N3 are preset by human, which can be set by the implementer, and the present application does not have special limitations.

[0052] For the B phase and the C phase, the ground fault identification value of the B phase and the ground fault identification value of the C phase are obtained by the same method as the ground fault identification value of the A phase.

[0053] When the ground fault identification value of any one phase is the first preset constant, it is determined that the any one phase is a fault phase, and it is determined that the power supply of the power supply panel has a ground fault. The power supply of the power supply panel is switched from the main power supply to the standby power supply, and the switching mode is as shown in step S106. Further, the ground fault signal is transmitted to the maintenance personnel, and after the maintenance is completed, the maintenance personnel switches the power supply of the power supply panel from the standby power supply to the main power supply through the manual control button of the power supply panel.

[0054] If only the phase to be analyzed exists, that is, the ground fault identification value is the second preset constant, the following steps are used for analysis.

[0055] In step S103, if only the phase to be analyzed exists, the periodic zero point sequence of each phase is obtained by analyzing the zero sequence fault of the power supply panel.

[0056] The zero sequence fault of the power supply panel refers to that when the three-phase voltage of the power supply is unbalanced, the sum of the phasors of the three voltage phases is not zero. For the voltage data collected by the present application, the sum of the voltage data of the three phases at the same time is not zero, and the phase difference between adjacent phases is not equal to

[0057] Based on the above analysis, first, the time when the voltage data of each phase is 0 is obtained. The waveform of single-phase voltage in alternating current is a sine wave, but due to the instability of the voltage in the power supply and the influence of environmental noise, there may be multiple 0 elements in the collected voltage data in a short time range. For 50Hz alternating current, every cycle of alternating current needs time, and half a cycle of alternating current needs There is a small time interval between the zero point caused by voltage instability and environmental noise and the cycle zero point, which is less than half the AC cycle time. The cycle zero point refers to the intersection of the ideal sine wave and the Y=0 axis.

[0058] Furthermore, the moment when the voltage data is 0 is recorded as the 0-value moment. For any phase, the order of all the 0-value moments in the preset neighboring time domain of each 0-value moment in all acquisition moments is arranged from small to large to form a time series of each 0-value moment, and the mean of all elements in each time series is calculated. In this embodiment, the preset neighboring time domain of each 0-value moment is the time series centered at each 0-value moment. time interval.

[0059] Furthermore, the number of samples of voltage data within half an AC cycle is obtained, and the expression is:

[0060] Wherein, L represents the number of samples of voltage data within half an AC cycle; a represents a preset value. In this embodiment, the value of a is 2, which is used to take half an AC cycle; P represents the number of voltage data collected within a preset time length; and n represents the number of AC cycles within the preset time length.

[0061] In this embodiment, the value of the preset time length is 1s. The value of the preset time length is preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0062] Furthermore, the period zero point difference of each element in each time series is calculated based on the distribution of elements in each time series and its adjacent previous time series, as well as the number of voltage data samples within half an AC cycle. The expression is:

[0063] hz j,k =|z j,k -Z j-1 -L|; where hz j,k represents the periodic zero-point difference of the kth element in the jth time series; z j,k represents the kth element in the jth time series; Z j-1 represents the cycle zero point of the j-1th time series; L represents the number of samples of voltage data within half an AC cycle.

[0064] It should be noted that: when the difference between the period zero points of any element in the time series is smaller, it means that the distance between the said element and the previous period zero point is closer to half an AC cycle, which means that the possibility that the said element is the period zero point is higher. Therefore, the element with the smallest difference between the period zero points in each time series is taken as the period zero point of each time series.

[0065] The cycle zero points of each phase are arranged in time sequence respectively to form a cycle zero point sequence of each phase.

[0066] In step S104, the difference between the same position elements of the cycle zero point sequences of any two phases is calculated, and the phase deviation between the any two phases is obtained by combining the deviation between the difference and a preset standard difference.

[0067] For normal 3-phase alternating current, the phase deviation between adjacent phases is Therefore, by comparing the difference between the actual phase deviation between adjacent phases and , the phase deviation between adjacent phases is calculated, and the specific calculation formula is:

[0068]

[0069]

[0070] In the formula, Pl A,B , Pl A,C , and Pl B,C respectively represent the phase deviations between A phase and B phase, A phase and C phase, and B phase and C phase; M A,B , M A,C , and M B,C respectively represent the minimum values of the number of elements in the cycle zero point sequences of A phase and B phase, A phase and C phase, and B phase and C phase; Z A,x , Z B,x , and Z C,x respectively represent the xth elements in the cycle zero point sequences of A phase, B phase, and C phase; 2π represents the sum of the phase deviations between any two adjacent phases; represents the phase deviation between any two phases under normal circumstances; P represents the number of voltage data collected within a preset time length; and n represents the number of alternating current cycles within the preset time length.

[0071] It should be noted that the greater the phase deviation, the higher the phase imbalance degree of the 3-phase alternating current, indicating that the zero sequence fault of the power supply screen power supply is more serious. Therefore, when monitoring and processing the power supply screen power supply, the greater the phase deviation, the more attention should be paid, and timely measures should be taken for adjustment and repair. In the power system, keeping the phase deviation small can ensure the stability and reliability of the power supply, provide high-quality power supply for users, and enhance the safety and stability of the power system.

[0072] In step S105, the power supply switching of the power supply screen is controlled based on the phase deviation.

[0073] Generally, in the operation process of the three-phase alternating current power supply, due to the influence of environment and other factors, the phase difference between adjacent phases of the three-phase alternating current power supply can exist a certain deviation, when the deviation is within a small range, it is a normal phenomenon, in the embodiment, if the phase deviation between adjacent phases is less than the second preset value, it is determined that the phase difference between adjacent phases is normal, otherwise, it is determined that the phase difference between adjacent phases is abnormal, and the power supply of the power supply panel needs to be switched immediately, that is, the power supply of the power supply panel is switched from the main power supply to the standby power supply, and the switching mode is as step S106. After the power supply of the power supply panel is switched from the main power supply to the standby power supply, according to the phase deviation greater than the second preset value, the digital phase-locked loop is used to correct the phase corresponding to the phase deviation greater than the second preset value, and after the correction is completed, the digital phase-locked loop sends a signal to the automatic switching circuit of the power supply panel, and the automatic switching circuit of the power supply panel switches the power supply of the power supply panel from the standby power supply to the main power supply.

[0074] In the embodiment, the value of the second preset value is 3°, and the value of the second preset value is preset by human, and the implementer can set a smaller value to ensure that the phase deviation is controlled within a smaller range.

[0075] Step S106, switching control of the power supply panel power supply.

[0076] Before the power supply of the power supply panel is switched from the main power supply to the standby power supply, the standby power supply is detected to detect whether the standby power supply has been successfully started, whether the output voltage and frequency are within the preset range. When the standby power supply has been successfully started and the output voltage and frequency are within the preset range, it indicates that the standby power supply is in a normal power supply state, and the switching operation is performed on the premise that the standby power supply is in a normal power supply state, otherwise, the switching operation is not performed. At the same time, in order to prevent misoperation in the switching process, a certain delay time and switching judgment logic are set, such as detecting the fault signal multiple times before switching. When the main power supply works normally, the contactor of the main power supply is powered on and attracted, and at the same time, its normally closed contact is opened, so that the time relay cannot be powered on, and it is ensured that the standby power supply will not work. When switching, the main power supply is powered off, and the time relay starts timing. After the time relay is powered on, its normally open contact is closed to form a self-locking loop, so that the contactor of the standby power supply is powered on and attracted. At this time, the standby power supply starts to supply power. Figure 3 The switching control flow chart of the power supply panel power supply.

[0077] In the embodiment, the switching is performed after detecting the fault signal for 3 times, wherein 3 is only an embodiment of the application, and the implementer can set the specific value according to the actual situation.

[0078] In this embodiment, the preset range of the single-phase output voltage of the backup power supply is 200V-240V, and the preset range of the frequency is 45Hz-55Hz. The preset range of the single-phase output voltage of the backup power supply and the preset range of the frequency can be limited by the implementer according to the actual situation, and the application does not make special limitations.

[0079] Based on the same inventive concept as the above method, the embodiments of the application also provide a power supply control system of a secondary power distribution power panel, which comprises a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of any one of the methods in the above power supply control method of the secondary power distribution power panel.

[0080] In summary, according to the change characteristics of the voltage data of the fault phase and the normal phase when the power supply of the power panel appears a grounding fault, the application compares the effective value of the voltage data of each phase within a preset time length with a preset threshold value to determine whether the power supply of the power panel appears a grounding fault. If a grounding fault appears, the power supply of the power panel is switched from the main power supply to the backup power supply, which can ensure the stable operation of the power panel. Further, by analyzing the time distribution of the voltage data being 0 and calculating the cycle zero point of each phase, the cycle zero point generated due to voltage instability and environmental noise can be avoided, which further improves the accuracy of calculating the phase deviation between adjacent phases according to the cycle zero point, determines whether the phase deviation between adjacent phases exceeds the normal range, and switches the power supply of the power panel from the main power supply to the backup power supply if it exceeds. This avoids the situation that the main power supply is still used for power supply when the phase deviation of the main power supply is abnormal, which affects the stability of the output power. By analyzing the voltage data during the operation of the power panel, various faults of the power supply of the power panel can be found in time, the sensitivity of fault detection of the power supply of the power panel is improved, accurate basis is provided for the switching control of the power supply of the power panel, and the stable operation of the power supply of the power panel is ensured.

[0081] The computer program instructions can also be loaded onto a computer, other programmable data processing apparatus, or other processing devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other processing devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions / acts specified in the flow diagrams and / or block diagrams.

[0082] It is apparent that a person skilled in the art can make a variety of modifications to the application described above without departing from the spirit and scope of the application. Therefore, the above-described embodiments of the application are intended to be illustrative only and not restrictive.

Claims

1. A power supply control method for a power supply panel of a secondary power distribution, characterized in that: The method comprises the following steps: Collect voltage data of each phase of the power panel during operation within a preset time period; By comparing the effective value of the voltage data of each phase within the preset time period with the preset threshold, the fault phase and the phase to be analyzed are extracted. If there is at least one faulty phase, the power supply of the power panel is switched; If there is only the phase to be analyzed, the periodic zero point sequence of each phase can be obtained by analyzing the zero sequence fault of the power supply panel; Calculating the difference between the elements at the same position in the periodic zero point sequences of any two phases, and combining the deviation between the difference and a preset standard difference to obtain the phase deviation between the any two phases; Based on the phase deviation, power switching of the power panel is controlled; The method for extracting the fault phase and the phase to be analyzed is: The effective value is the root mean square value of all voltage data of each phase within the preset time period; When the effective value of any phase is less than a preset first threshold, determining that any phase is a fault phase; When the effective value of any phase is greater than or equal to the preset first threshold and less than or equal to a preset second threshold, the any phase is determined to be the phase to be analyzed.

2. A power supply control method for a power supply panel of a secondary power distribution as claimed in claim 1, characterized in that: The acquisition process of the periodic zero point sequence is: Recording the moment when the voltage data is 0 as the zero-value moment, for any phase, arranging the order of all the zero-value moments in the preset neighboring time domains of each zero-value moment in all acquisition moments from small to large to form a time series of each zero-value moment; calculating the mean of all elements in each time series; For any time series and its adjacent previous time series, calculate the difference between each element in the any time series and the mean of the previous time series; Obtaining a period zero point difference of each element in the any time series by comparing a first preset value with the difference corresponding to each element in the any time series, and extracting an element as a period zero point from the any time series based on the period zero point difference; All periodic zero points of any phase are arranged in time sequence to form a periodic zero point sequence of any phase.

3. A power supply control method for a power supply panel of a secondary power distribution as claimed in claim 2, characterized in that: The period zero point difference is a difference value between the first preset value and the difference value corresponding to each element in any time series.

4. A power supply control method for a power supply panel of a secondary power distribution as claimed in claim 2, characterized in that: The period zero point is the element with the smallest period zero point difference in any time series.

5. The power control method for a power supply panel of a secondary power distribution as claimed in claim 1, characterized in that: The calculation formula of the phase deviation is: Where, Indicates the phase deviation between phase A and phase B; Indicates the minimum number of elements in the periodic zero point sequence of phase A and phase B; 、 Represent the xth element in the periodic zero point sequence of phase A and phase B respectively; P represents the number of voltage data collected within a preset time length; n represents the number of AC cycles within the preset time length; According to the calculation method of the phase deviation between phase A and phase B, the phase deviation between phase A and phase C and the phase deviation between phase B and phase C are calculated respectively.

6. A power supply control method for a power supply panel of a secondary power distribution as claimed in claim 1, characterized in that: When the phase deviations between any two phases are all smaller than the second preset value, the power supply of the power panel is not switched; otherwise, the power supply of the power panel is switched.

7. A power supply control method for a power supply panel of a secondary power distribution as claimed in claim 1, characterized in that: Before switching the power supply of the power panel, it is necessary to detect the startup status of the backup power supply and the distribution of output voltage and frequency.

8. A power supply control method for a power supply panel of a secondary power distribution as claimed in claim 6, characterized in that: After the power supply of the power supply panel is switched from the main power supply to the backup power supply, feedback control technology is used to correct the phase corresponding to the phase deviation greater than the second preset value based on the phase deviation greater than the second preset value. After the correction is completed, the power supply of the power supply panel is switched from the backup power supply to the main power supply.

9. A power supply control system for a secondary power distribution power supply panel, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the power supply control method for a secondary power distribution power supply panel as described in any one of claims 1-8 are implemented.

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